On the justification of Dempster's rule of combination

In Dempster-Shafer theory it is claimed that the pooling of evidence is reflected by Dempster's rule of combination, provided certain requirements are met. The justification of this claim is problematic, since the existing formulations of the requirements for the use of Dempster's rule are not completely clear. In this paper, randomly coded messages, Shafer's canonical examples for Dempster-Shafer theory, are employed to clarify these requirements and to evaluate Dempster's rule. The range of applicability of Dempster-Shafer theory will turn out to be rather limited. Further, it will be argued that the mentioned requirements do not guarantee the validity of the rule and some possible additional conditions will be described